Each generation takes a special pleasure in removing the household gods of its parents from their pedestals, and consigning them to the cupboard. The prophet or pioneer, after being at first declared to be unintelligible or absurd, has a brief spell of popularity, after which he is said to be conventional, and then antiquated. We may find more than one reason for this. A movement has more to fear from its disciples than from its critics. The great man is linked to his age by his weakest side; and his epigoni, who are not great men, caricature his message and make it ridiculous. Besides, every movement is a reaction, and generates counter reactions. The pendulum swings backwards and forwards. Every institution not only carries within it the seeds of its own dissolution, but prepares the way for its most hated rival.

The German Von Eicken found, in this tendency of all human movements to provoke violent reactions, the master key of history. Every idea or institution passes into its opposite. For instance, Roman imperialism, which was created by an intense national consciousness, ended by destroying the nationality of rulers and subjects alike. The fanatical nationalism of the Jews left them a people without a country. The Catholic Church began by renouncing the world, and became the heir of the defunct Roman empire. In political philosophy, the law of the swinging pendulum may act as a salutary cold douche. Universal suffrage, says Sybel, has always heralded the end of parliamentary government. Tocqueville caps this by saying that the more successful a democracy is in levelling a population, the less will be the resistance which the next despotism will encounter.

But the pendulum sometimes swings very slowly, and oscillates within narrow limits; while at other times the changes are violent and rapid. The last century and a half, beginning with what Arnold Toynbee was the first to call the Industrial Revolution, has been a period of more rapid change than any other which history records. The French Revolution, which coincided with its first stages, helped to break the continuity between the old order and the new, and both by its direct influence and by the vigorous reactions which it generated cleft society into conflicting elements. Then followed a Great War, which shook the social structure to its base, and awakened into intense vitality the slumbering enthusiasm of nationality. At the same time, a variety of mechanical inventions gave man an entirely new control over the forces of nature and a new knowledge of the laws of nature, and this new knowledge, not content with practical applications, soon revolutionised all the natural sciences, and profoundly affected both religion and philosophy. The reign of Queen Victoria, which I have chosen to mark the limits of my survey to day, covered the latter half of this saeculum mirabile , the most wonderful century in human history.